Posts tagged chroot

linux: chroot and reinstall grub2

posted on 2015-10-02 01:53:04

First, while in the live disk (i.e. grml) you just booted, mount everthing to a folder, which will be the chroot root. I.e. ~/asdf.

cd
mkdir asdf
mount /dev/sda1 asdf
cd asdf

After cd'ing into there you have to mount some special folders:

  • /proc
  • /sys
  • /dev
  • /dev/pts
  • /run

Like this:

mount  -t      proc   proc       ./proc
mount  -t      sysfs  sys        ./sys
mount  --bind         /dev       ./dev
mount  -t      devpts devpts     ./dev/pts
mount  --bind         /run       ./run

Possibly you need to mount /boot and /boot/efi, too, if your boot partition is separate and if you have a UEFI setup.

followed by:

chroot .

Should you use a grml live disk and it is complaining about a missing zsh shell:

chroot . /bin/bash

Then reinstall grub:

<!-- grub2-install --recheck --no-floppy /dev/sda -->
<!-- grub2-mkconfig -o /boot/grub2/grub.cfg -->
<!-- mkinitrd -->
grub-install /dev/sda
update-grub

Exit the chroot and reboot.

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